"He went to the United Nations and criticized Israel for building settlements," Romney went on. "He had nothing to say about Hamas' 20,000 rockets into Israel. We will stand with our friends."

But when it comes to diplomatic relations, Romney may have already picked a fight with another U.S. ally -- this one just next door.

In a campaign white paper on U.S. global leadership released last fall, Romney wrote:

We must also contend with failed or failing states, like Somalia, Yemen, Afghanistan, and Pakistan, and to an alarming degree, our southern neighbor Mexico. These are states with weak governance that are wracked by poverty, disease, internal strife, refugees, drugs, and organized crime. They are or can become safe-havens for terrorists, pirates, and other kinds of criminal networks. Their problems regularly spill across borders turning internal problems into regional and even global ones.

Somalia, Yemen, Afghanistan ... and Mexico?

It's not the first time the term "failed state" has been used to describe America's southern neighbor in U.S. policy circles. Toward the end of the Bush administration, several leaked government reports painted a dire picture of a Mexican federal government deeply incapable of handling the criminal and drug enterprises that continue spilling into the United States.

Experts on Mexico's government, however, say such rhetoric has been overblown.

"Not a failed state," said George Grayson, a professor of government at the College of William and Mary, and author of "Mexico: Narco Violence and a Failed State?"

"Strong institutions such as the Church, the business sector, the banking system, the armed forces, the political parties, contiguity to the U.S., and a sense of national cohesion (missing in much of the Mideast) militate against Mexico's become a failed state," Grayson said in an email. "There are some individual states such as Guerrero and Oaxaca that might be considered failures, but not the country as a whole."

Indeed, not long after the Bush administration criticisms of Mexico leaked, officials there responded with deep resentment. When the Obama administration took over, they were compelled to attempt serious damage control, quickly sending Hillary Clinton to Mexico City. A few weeks later, Obama himself visited.

That didn't inoculate the Obama administration against further diplomatic flaps, though. The president was later forced to recall his ambassador to Mexico City, after frank discussion the government's drug-war floundering surfaced in the WikiLeaks cables. (The ambassador, Carlos Pascual, was also reportedly dating the daughter of an opposition politician at the time.)

"Mr. Romney probably needs a bit more exposure to actual failed states (like Somalia, Chad, and Sudan) before making such an assertion about Mexico," David Shirk, a political science professor and expert in U.S.-Mexican relations at the University of San Diego, wrote in an email.

"No one who has ever been to a failed state believes that Mexico fits into this category," Shirk said, though he said some "isolated 'captured spaces'" in the country may be ungoverned.

Added Shirk: "It seems like Romney is trying to take a tough stance on Mexico partly as a means to distinguish himself from candidates like Rick Perry and Newt Gingrich."

A Romney spokesman did not respond to a request for comment.

If Romney keeps his head down, the flap is likely to blow over, Grayson said, given his relatively good timing.

"Truth be told, the Mexicans are fixated on their July 1, 2012 presidential election," he said, "and do not give a tired rat's derriere about what Romney calls their country."